If both the annotation and the value labels of an item match the pattern the query
method for ‘item’ objects returns a list containing the annotation and the value labels,
otherwise if only the annotation or the value labels match the pattern, either the
annotation or the value labels are returned, otherwise if neither matches the pattern,
query returns NULL.

The methods of query for ‘data.set’ and ‘importer’ objects return a list of all
non-NULL query results of all items contained by these objects, or NULL.